If a plant is to be grown in a flowerpot, the soil of the flowerpot has to have a proper water content, and has to be kept in a proper level of water content. Usually, the sizes of flowerpots are limited, and therefore, keeping the water content level is difficult when supplying water. Therefore, in most cases, a sufficient amount of water is supplied at a given time, and after elapsing of a period, water is supplied again before the soil of the flowerpot is completely dried. The supplying of water to a flowerpot can be different in its amount and period depending on the kind of plant, the size of flowerpot, the water storing capability of the soil, the ambient temperature, and the like, but generally, the water supplying has to be carried out periodically at the intervals of 1 to 3 days.
In the case where large quantities of plants are grown, the water supplying can be carried out by means of a mechanical apparatus, and in such a case, even if the managing person is absent, the water supplying can be automatically conducted.
However, in the case where small quantities of plants are grown with flowerpots in a home, the managing person has to supply water periodically in a manual method. Therefore, if the managing person is out of the home on a touring trip or on a business trip, the plants can be withered to death due to the failure of supplying of water.
Meanwhile, it can be contemplated that a flowerpot is put into a basin containing a certain amount of water as a measure against the failure of periodical water supplying. However, in such a case, the soil will take in and contain too much water, with the result that the air flow through the soil is blocked, and that the roots of the plant are impeded from growing or are decayed. Therefore, when a supplying of water is carried out, it has to be assured that the water supply should not cause a blocking of the air flow through the soil.